Plus, aren't pulse oximeters consider medical equipment and you need a Dr. Order to buy one? Maybe I'm wrong but I don't think I am.
Let me ask the collective hive here. What do you think of the EMT or Medic who stops on scene to help the person, you arrive and are met by said EMT who has put the patient on oxygen and a pulse ox. Seriously, what are your initial thoughts about this person on scene?
I've been on both sides of the coin. More often on the negative response from the arriving ambulance than good.
Was told by a fireman who was the only guy to get on scene in a fire truck. Ambulance and other trucks still on the way. Rollover accident on the interstate. Three patients, three ejections, 2 of three critical. The guy tells me, "You can leave now, I've got it" I told him I wasn't leaving. He got pissy, said I'm the shift captain and I'm in charge. I said fine, are you a medic or EMT? He said emt. I said I'm a medic, I've already begun treating these people, they are your patients but I'm the highest medical person on scene so they are mine until your ambulance gets here.
First arriving law enforcement officer arrives, the fireman tells him to remove me from the scene. I told the cop the same thing and the cop said I could stay. When the ambulance got there I gave them report and they said thanks. I did tell the medic as we were loading one into the ambulance that the captain tried to force me off the scene and the medic said "The guys a tool. He's the last person I would want treating my dog" or something to that effect. I sent a letter to the fire department but I never received a response.
I also had a great response from a small ambulance service when our ambulance stopped at a bad crash. We initiated treatment, resuscitation as a matter of fact. Ejected patient with significant head injury. Crash just happened. We had patient intubated and worked the patient until the responding ambulance arrived. Got a letter of thanks to my EMS Supervisor for the help on that one.
But seriously, think about what your response would be to the off duty emt or medic, out of their jurisdiction helping out by putting Oxygen and a pulse ox on the patient? I'm sure viscerally it's a negative one.